1. Field of the Invention
The present invention relates to an optical disc recording apparatus which records data on an optical disc standardized by the International Standard Organization (ISO), more particularly, the invention relates to a technique of controlling recording power available for recording data on those optical discs having different recording sensitivity in the ISO standard.
2. Description of Related Art
Today, an optical disc serving itself as interchangeable recording medium containing vase potential capacity has attracted growing attention of all the concerned. Actually, the optical disc is applied to a wide variety of uses typically including the recording of image data for example. The international Standard organization sequentially standardizes a variety of optical discs including the one having 130 mm of diameter.
FIG. 1 schematically designates composition of data recording areas of an ISO-standard optical disc 17. The regions called "control tracks" in which the control data is recorded are compulsorily provided on the internal and external circumferential surfaces of the optical disk 17. A plurality of regions called "phased encoded parts (PEP)" are provided on an annular region between radiuses 29 mm through 29.5 mm of the control tracks CT on the side of the internal circumference. On the other hand, a plurality of regions called "standard format parts (SFP)" are provided on one annular region between radiuses 29.52 mm through 29.7 mm and the other annular region between radiuses 60.15 mm through 60.5 mm of the control tracks CT on the internal and external circumferential surfaces. The regions sandwiched by the control track CT on the side of the internal circumference and the other control track CT on the side of the external circumference are user areas.
There are three regions of the "phased encoded part (PEP)" including PEP1, PEP2 and PEP3, each preliminarily being formulated by triplicated 18 bytes. However, no track slit is provided for these regions PEP1, PEP2 and PEP 3, and yet, unlike the user areas, control data are preliminarily recorded thereon with sparse density. A variety of coded data containing inverted phases are preliminarily recorded on these PEP1, PEP2 and PEP3, where these coded data include identification data to discriminatively identify the recording format whether being the "additional data writing type" or the "magneto-optic type". The phase-inverted-code recorded data also includes the data for reading the "standard format part (SFP)" and the vendor code. For example, the optical disc format data is recorded in the upper 4 bits of the byte 7 of the PEP regions. While the "additional data writing mode" is underway, all the predetermined bits 5 respectively remain to be "1".
A plurality of "standard format part" including SFP.sub.1 through SFP.sub.n (where "n" designates the number of sector) are preliminarily formulated every sector in the annular region between radiuses 29.52 mm through 29.7 mm that follow PEP1, PEP2 and PEPS of the control track CT and also in the annular region between radiuses 60.15 mm through 60.5 mm. Those SFP regions respectively contain track slits in which the recording and reproducing data are respectively recorded with the density identical to that in the user areas. Those SFP regions are provided by way of equally dividing the tracks in the direction of the inner circumference. For example, the ISO standard prescribes the number "n" of sector to be either 17 or 31. When there are 17 sectors, each of these sectors has 1024 bytes of the user data area. On the other hand, when there are 31 sectors, each sector has 512 bytes of the user data area.
Each SFP regions has 512 bytes when n is 31. Of these, data duplicated from the PEP regions are recorded in 18 bytes which ranges from byte 0 through byte 17. Medium data for the recording and reproducing of the optical disc are recorded in 366 bytes which ranges from the 18th byte to the 383rd byte. System data like the number of byte of the user area are recorded in 64 bytes which ranges from the 384th byte to the 477th byte. The remaining bytes ranging from the 448th byte to the 511th byte are respectively reserved for the introduction of further standards in the future and any contingent standard other than the anticipated ISO standards.
The detail of the composition of those functional regions of the ISO-standard optical disc as per the above description is shown in Table 1, on page 42, 16.4.3.2, of the ISO/IEC DIS 10089:1991.
Conditions of the reflectivity and the intensity of light against three kinds of laser beam wavelength are respectively predetermined in reference to the regions containing the recorded medium data. The light intensity is specified against a variety of laser beam wavelength relative to the rotation frequency of the four kinds of optical discs. Concretely, a total of 12 degrees of the light intensity are prescribed by the ISO standard. Furthermore, additional conditions are prescribed on the light intensity. Concretely, when a constant pulse width system is introduced, three kinds of specifications are applied to the radius available for the recording area. When three kinds of pulse width are made available, a total of 9 kinds of conditions are prescribed on the light intensity. In addition, when a constant power system is introduced, four kinds of conditions containing the light intensity and three kinds of radiuses. As is done for conditioning the recording requirements, specific data on the data erasing condition is also stored in those SFP regions. Concretely, when introducing a constant pulse width system, the SFP regions respectively store data for conditioning the light intensity during the recording and erasing modes to rule those requirements including the following; three kinds of the combination of wavelength (.lambda.1 through .lambda.3) with the reflectivity, four kinds of the rotation frequencies of the optical disc (N1 through N4), three kinds of radiuses (30 mm, 45 mm, and 60 mm) of the optical disc, and three kinds of pulse width (T.times.1.0, T.times.0.5, and T.times.0.25), respectively.
Incidentally, the ISO standard also prescribes the entry of the standard recording condition when merely introducing one kind of the laser beam wavelength (.lambda.1=825 nm) and the rotation frequency of the optical disc (N1=1,800 r.p.m.). On the other hand, it is optional to write the recording condition when applying other wavelength including .lambda.2 and .lambda.3 and other rotation frequencies of the optical disc (N2, N3 and N4). In other words, if the recording condition compatible with the rotation frequency of the optical disc recording apparatus were not written in the optical disc itself, no data can be recorded on this optical disc at all.
Furthermore, even when using an optical disc fully compatible with the ISO standard, recording sensitivity like thermal capacitance of recording layer may contingently differ from each other. As a result, even when rotating the optical disc based on the rotation frequency identical to other optical discs, recording condition differs from each disc having different recording sensitivity. In consequence, compared to other recording media like a floppy disc or a magnetic disc, those optical discs conforming to the ISO standard cannot perfectly be interchangeable. In other words, even when those recording conditions compatible with the rotation frequency of the optical disc recording apparatus are properly written in each optical disc, the recording condition still lacks in enough flexibility, and thus, the data recording operation cannot be executed under the optimal condition.